Question

why do we need standard unit
y do we need standard unit

Answer 1

Standard unit of measurement provides a reference point by which objects of weight, length or capacity can be described. Standard units are the units used all over the world for measuring a particular quantity. The need of a standard unit arises when we deal with people when from other places

Answer 2

We need standard unit so that all the people in the world can understand what you mean by a certain quantity...
for example: if u say something 1 handspan long then everyone will not get the exact value of the length of that thing because each and every person hand is of different length... but if you suppose 1 m then everybody can understand how much is the length of that thing...

Hope it helps...